The prevalence of problem behaviors increases dramatically during adolescence. Problem behaviors such as school misconduct, underachievement, and dropout; tobacco, alcohol, and other drug use; violence and delinquency place youth at an increased risk for school failure, involvement in the criminal justice system, and chronic substance abuse. This study is an efficacy trial of school-based interventions designed to reduce the prevalence of problem behavior among middle school students. By 7th grade, students in schools that received the social skills curriculum and parent intervention were less likely to smoke or engage in other problem behaviors and reported greater parental involvement and higher achievement motivation than students in the control schools.